How to Remember TextView Size with Shared Preferences in Android Apps

Описание: Learn how to save and retrieve TextView size using Shared Preferences in your Android app to enhance user experience and accessibility.
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This video is based on the question https://stackoverflow.com/q/66482761/ asked by the user 'biskyy' ( https://stackoverflow.com/u/12255771/ ) and on the answer https://stackoverflow.com/a/66483395/ provided by the user 'Amin Mousavi' ( https://stackoverflow.com/u/2940733/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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How to Remember TextView Size with Shared Preferences in Android Apps

Creating a user-friendly application often involves enhancing accessibility features, such as allowing users to adjust text sizes for better readability. In this guide, we’ll tackle how to remember the size of a TextView after the user leaves your Android application.

The Problem at Hand

In the context of your songbook app, you have implemented zoom functionality to change the lyrics' text size. However, you've noticed that the app does not retain the last used text size when the user reopens the app. You attempted to use Shared Preferences for this purpose, but it didn't work as expected. Let's fix that!

Understanding Shared Preferences

Shared Preferences is a simple way to store small amounts of data, such as user settings or configurations, in Android. It works like a lightweight database for key-value pairs allowing you to save and retrieve the information easily.

Analyzing Your Code

Let's break down the code you're currently using and identify the key issues:

Initialization of mTextSize:

The mTextSize variable is initialized with a default value of 50f. So every time the app starts, it begins with this value without considering any previously saved settings.

Setting the Text Size:

In your onCreate method, you set songString.textSize directly from Shared Preferences but do not update mTextSize accordingly. As a result, the first zoom in/out actions revert the text size back to 50f.

Using Complex Units:

When setting the text size, it’s important to specify the unit (in this case, pixels) using the TypedValue.COMPLEX_UNIT_PX option. You missed this when initializing the text size from Shared Preferences.

Step-by-Step Solution

Here’s how you can modify your code to make it work correctly:

1. Update Initialization

In the onCreate method, set mTextSize based on the value retrieved from Shared Preferences before applying it to your TextView.

2. Set Text Size with Units

Make sure to include the unit designation when you set the text size for the TextView.

Revised Code Example

Here's the code with the necessary corrections:

[[See Video to Reveal this Text or Code Snippet]]

3. Adjust Zoom In and Zoom Out Actions

Ensure that when the user zooms in or out, you save the new text size to Shared Preferences:

[[See Video to Reveal this Text or Code Snippet]]

Conclusion

By implementing these changes, you will enable your app to remember the user’s preferred text size even after they exit. This enhances user experience, especially for those who may rely on larger text for readability. Utilize Shared Preferences effectively to make your app more user-centric!

Feel free to test and implement these changes in your songbook app, and watch as your users enjoy a seamless reading experience!